Legend:

If you follow the tutorial to create a particle system, you'll end up with a scene graph that looks something like the figure on the left. The Particle System (Drawable) is a child of a geode that has as it's parent the root node. The other particle system elements (Modular Program, Updater and Emitter are under a transform associated with our model. This gives us 'well behaved' particle systems: In the case of the tutorial the dust effect follows the tank around the scene. The particle system drawables are not under the vehicle transform and life is good.[[BR]]